Progressive Cavity Pumps for Clay Processing (Kaolin)

How are the internal failing? These pumps fail for three main reasons, dry running, abrasion (wrong material selection) and over pressure. Remember they are a PD pump so if your operators are treating them the same way as they did the centrifugals then you are in trouble.

If you are more specific about the failure mode we could possibly help some more.

is there a bypass to relieve overpressure when all flows to the dies are stopped. A PD pump will break or stall if the flow is stopped with no bypass.

Usually the makers provide them, but with a highly viscout fluid, they might need adjustments.

Why were the old type removed?

Getting the hint from your statement that it replaces the centrifugal pump service and water may contain some clay or clay slurry, I am mostly suspicious the abrasion by foreign material induced into pump casing.

I am not insisting that any centrifugal pump is the answer to the slurry service, but it is quite true that PD pump is much much more susceptible to the abrasive service.

Why did you replace the centrifugal pumps with PD pumps? Wasn't there any slow-proceeding abrasion or wearing inside the casing by the pumping liquid?

If it is true, I would recommend to replace the pump again with the slurry service pump. It is also centrifugal pump. You can contact any pump supplyer near your plant for further consultation.

Your pump speed very important, slurry moisture and operating pressure are the first places to start looking, you do not want to be running very fast with a clay slurry.

What kind of failures are you having, stator failures?

Note that any positive displacement pump is very sensitive to anytype of contamination.

We have not worked with these pumps though the progressive cavity pumps are supposed to be quite friendly with some degree of contamination.

Why have you gone PD pump against the centrifugal pump ? the roto dynamic pumps are supposed to be more friendly for the slurries/ contaminants and most common pump for slurry pumping is the centrifugal pump, for obvious reasons.

In certain areas we do use PD pumps for slurries, in these, some soft wearing liners are kept (usually brass) which are changed regularly. But these are not the 24x7 cycle pumps and the slurry is required at a high pressure, thus negating the use of centrifugal pump.

Check this link, may be useful

http://www.pump-zone.com/articles/127.pdf

Hello

Your using Progressive Cavity pumps on a very abrasive application. You need to look at a couple of things. The varying viscosity and dry solids content and specific gravity. Per stage of a PC pump will give you 6bar operating pressure so I am assuming that it wont be to a high pressure application because the higher the pressure the faster the wear factor. Then look at rotor/stator geometry. By changing the geometry you can increase the flow but the drawback is that you increase the speed and accelerate the wear again. I think if you were using an end suction centrifug, it must have been small because there is no way a PC pump can compete on flow rate. unless you run them very fast or they are considerably larger than the centrifug pump.

Summary

You need to run the PC pump around 200 rpm or slower if possible.

The higher the pressure the quicker the wear factor

If you are going to use a PC pump then Netzsch would be your best bet. If you are determined to use PD technology then I would consider a Boerger Rotary Lobe pumps. It wont out perform the PC pump but the spares will be considerably cheaper and you can change them out quicker

My choice would be an ITT Gould's 3185 Slurry pump with an IFrame 5 years warranty no queries

Hope that helps come back to me if you need more specific info on PC application I have all the data you would need.